Garbage - Avoid where possible! I've seen probably 1,000+ movies in my life. I've seen some fantastic movies, and I've seen some that are so bad, you wonder how they were financed. Then there's My Super Ex-Girlfriend.
I watched this with my wife thinking it would be a chick-flick (or something), but neither of us knew what we were in for. It was SO bad, we couldn't turn it off, because we had to see how it ended - and we weren't surprised that the ending sucked just as hard as the rest of the movie.
How they managed to get the likes of Uma Thurman to do this movie is beyond me. Either she is desperate for cash, or she is doing someone a favour. I'm going for option #2.
Normally for a bad movie, I'd say "hold out seeing this at the movies and wait for it to go weekly on DVD". For this movie, I'd say "Don't see it at the movies. Don't rent it. And if your friend invites you over to watch it, say you're doing something else. You'll thank me for it." IMDb only allows for a rating of 1 - 10. So I had to give this a 1. If I could have given it a -10 I would have. There is no redeeming qualities in this movie at all to justify it getting a rating any higher.